Added write event handler reset in ngx_http_named_location(). On internal redirects this happens via ngx_http_handler() call, which is not called on named location redirect. As a result incorrect write handler remained (if previously set) and this might cause incorrect behaviour (likely request hang). Patch by Yichun Zhang (agentzh).

# Copyright (C) Igor Sysoev
# Copyright (C) Nginx, Inc.


cat << END >> $NGX_AUTO_CONFIG_H

#ifndef $have
#define $have  0
#endif

END